234 MAKtJAL OF CATTLE-FEEDING, 



troacen-free extract and tlie amount of substances soluble 

 in water, since the latter includes not only non-nitrogenous 

 matters but also larger or smaller quantities of protein 

 and asli. 



Tlie rule is to be considered as, at best, a purely empiri- 

 cal one, wliicli, to be sure, has some value for practical 

 purposes, since in general the digestibility of a coarse or 

 green fodder is greater the more solid matter can be ex- 

 tracted from it by boiling water, but to which no scientific 

 value can be attached. 



Crude Pat.-That the crude fat, or rather the ether 

 extract, of the coarse fodders is a mixture of the most 

 various substances, some of which are digestible and some 

 indigestible, has been already explained. The chlorophyll, 

 or green coloring matter of plants, is soluble in ether, but 

 seems to be entirely indigestible, and the wax-like sub- 

 stances most probably belong to the same category. 



It is therefore to be expected that the digestibility of the 

 crude fat will be very different according to the kind and 

 quality of thq fodder. It is always greater in young and 

 tender plants than in older ones, and it has also been ob- 

 served that the crude fat of clover hay and of the straw of 

 the legumes is generally more digestible than of that of 

 meadow hav and the straw of the cereals. 



Crude Protein. — The digestibility of crude protein in 

 the various kinds of coarse fodder is subject to greater 

 variations than that of almost any other constituent. Of 

 the protein in clover hay and meadow hay, e. ^., a quantity 

 varying, according to circumstances, from 35 per cent, to 

 75 per cent, of the total amount is digested. Generally 

 the protein is more easily and completely digested the 

 greater the percentage of it contained in the fodder, i. <?., 

 the narrower the nutritive ratio. At the same time, the 



